https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/160 2026-04-05T02:10:15Z 2026-04-05T02:10:15Z Park, Su-Seong Lee, Dong-Geun Kim, Rae-Young https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/211912 2026-04-02T06:30:26Z 2026-06-01T00:00:00Z

Title: Development of E-STATCOM analytical model for impact analysis of the southwest sea offshore wind farm linked system Authors: Park, Su-Seong; Lee, Dong-Geun; Kim, Rae-Young Abstract: An electromagnetic transient (EMT) analysis model is presented to evaluate the impact of large-scale offshore wind farm integration on the power system in the southwestern sea of Korea, in accordance with the 10th Basic Plan for Power Supply and Demand. An efficient E-STATCOM analysis model is developed by incorporating average representations of the MMC, DC–DC converter, and energy storage system (ESS) into an EMT framework, enabling system-level dynamic analysis with reduced computational burden while preserving essential transient behavior. Model parameters are derived based on power system characteristics and STATCOM ratings. The southwestern regional transmission system is converted into an EMT environment, and the operation and control modes of the proposed E-STATCOM are verified. The proposed model is comparatively evaluated against conventional EMT modeling approaches to assess dynamic fidelity and computational efficiency. The impact of E-STATCOM integration is analyzed mainly from voltage and frequency perspectives, considering variations in transmission lines, load conditions, and power generation before and after connection. The results confirm that the proposed EMT modeling framework provides an effective and scalable solution for analyzing large-scale offshore wind integration under weak-grid conditions. © 2026 The Authors.

2026-06-01T00:00:00Z So, Jongho Jeong, Inseok Maeng, Seonjeong Choi, Eunmi Kim, Minjoong Chung, Chin-Wook Yun, Ju-Young https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/209443 2026-01-17T02:31:12Z 2026-04-01T00:00:00Z

Title: Investigation of the interactions of NF3-based plasma with Y2O3 and YF3 coatings: Focus on contamination particle generation and wall redeposition Authors: So, Jongho; Jeong, Inseok; Maeng, Seonjeong; Choi, Eunmi; Kim, Minjoong; Chung, Chin-Wook; Yun, Ju-Young Abstract: This study investigates the interactions of Y2O3 and YF3 atmospheric plasma spraying (APS) coatings with NF3/ Ar/O2 plasma, focusing on their positions on chamber electrodes and walls. The electrode coatings showed mass loss due to ion bombardment, with YF3 experiencing more loss than Y2O3. Coatings on the walls gained mass from byproduct redeposition, with Y2O3 showing greater mass increase than YF3 due to its higher fluorine reactivity, which enhanced F radical absorption and promoted redeposition. Scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy revealed that fine particles on the coatings either agglomerated or were removed, with agglomerated particles exhibiting high fluorine intensity. The results emphasize the importance of selecting the appropriate material based on its position in the chamber, as this significantly affects contamination and redeposition behaviors. These findings are crucial for optimizing material selection in plasma applications, improving process stability and equipment lifespan.

2026-04-01T00:00:00Z Kim, Geon Kim, Dong-Joong Kim, Rae-Young Lee, Myoung-Jin https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/210882 2026-02-23T00:00:13Z 2026-03-01T00:00:00Z

Title: Impact of Duty Ratio and Saturation Cycling on Efficiency in Current-Fed Push-Pull DC/DC Converter with Active-Clamp Authors: Kim, Geon; Kim, Dong-Joong; Kim, Rae-Young; Lee, Myoung-Jin Abstract: This paper investigates the efficiency performance of a current-fed push-pull DC/DC converter incorporating an active-clamp circuit. The primary focus is to optimize the converter's efficiency by considering the influence of duty ratio and saturation cycling in the boost inductor. The study presents a new efficiency analysis model by incorporating theoretical, simulation, and experimental approaches. Through detailed analysis, the relationship between duty ratio, voltage gain, and efficiency is explored, with an emphasis on achieving high efficiency while minimizing input current ripple. This paper defines “saturation cycling” as a phenomenon that inherently arises when the boost inductor alternates between saturated and unsaturated states. This behavior is an unavoidable physical consequence of the design aimed at minimizing input current ripple. The results indicate that it is impossible to simultaneously achieve zero input ripple and maximum efficiency, thus necessitating careful duty ratio selection. Experimental validation confirms that the converter can reach efficiencies of up to 96.565%, demonstrating the robustness and performance of the proposed design. The findings suggest optimal design practices for high-efficiency power conversion in fuel cell applications and similar high-current energy conversion systems.

2026-03-01T00:00:00Z Seo, Beom-Jun Kim, Kyung-Hyun Ahn, Se-hun Kim, Deok-Hwan Jung, Un Jae Chung, Chin-Wook https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/211392 2026-03-19T09:00:35Z 2026-03-01T00:00:00Z

Title: Transparent electrical-optical probe for noninvasive plasma diagnostics Authors: Seo, Beom-Jun; Kim, Kyung-Hyun; Ahn, Se-hun; Kim, Deok-Hwan; Jung, Un Jae; Chung, Chin-Wook Abstract: We present a wall-mounted indium tin oxide (ITO)–glass probe that enables co-located, minimally invasive electrical–optical plasma diagnostics suitable for industrial semiconductor reactors. Since ITO is both transparent and highly conductive, this probe allows for simultaneous electrical and optical measurements from the chamber wall. Electrically, the primary challenge is that the ITO glass behaves as a series resistor–capacitor (RC) load. To address this, we generalize the floating harmonic method by developing a comprehensive RC load model. Our analysis reveals that even a modest series resistance (∼tens of ohms) can attenuate harmonic currents and alter their phase, causing conventional, purely capacitive models to significantly overestimate the electron temperature. Our modified model corrects for these distortions, yielding accurate electron temperature and plasma density. Optically, the argon metastable density and the relative oxygen radical density were measured using the line-ratio method and actinometry, respectively. Finally, photoresist etching experiments were performed in an oxygen plasma, and the etch rate was directly measured. By combining the electrical and optical plasma parameters obtained from our probe, the observed variations in the etch rate could be consistently interpreted. This integrated approach provides a robust and practical method for noninvasive process monitoring, enabling combined electrical and optical diagnostics using a single wall-mounted probe.

2026-03-01T00:00:00Z